class Age:
    def __get__(self, instance, owner):
        print("__get__")
        return instance.v
    def __set__(self, instance, value):
        print('__set__')
        instance.v= value
    def __delete__(self, instance):
        print("delete")

class Person:
    age = Age()

p = Person()
print(p.age)
p.age = 10
print(p.age)
# del p.age
